Description
The carapace of the dwarf crab is often covered with a hydroid. The width of the carapace is larger than its length. Males have stronger claws than females. They are fertile at the age of two, and the female first has to moult before she can mate, just like many other crab species. They will eat everything, even their own species.

Size
Carapace width is usually smaller than 23 mm.

Colour
The legs and carapace are dark greyish-green or dark brown to black, the bottom side of the claws are white and the tips of the claws as well.

Habitat
They prefer clay covered floors, with organic sediment. In the Veerse meer they often hide under stones. Usually at a depth up to 8 meters, but in the winter you will have to search deeper.

Distribution
Native from the Northwestern Atlantic. Introduced in Eastern Pacific and in Europe: scattered localities from Poland, Denmark, Great Britain (Cardiff), the Netherlands, Belgium, France, southwards to southwestern Spain; northern Adriatic, Black sea, Caspian Sea, Aral Sea.